i've checked all the vacuum lines they are good no cracks or missing lines. cleaned the injectors, put on new plugs and plug wires, regrounded the motor and the battery. changed the coils and checked compression. im running out of things it could be. any pointers??

 

still lost come on guys any help

 

how about timing..did you check that? and what do you mean by miss..? smog? or missfire..?

:AA:

 

come on guys i really need help with this one. the only thing i could think is i have a stuck apex. i've tryed everything else. replaced a lot of things and it still has a miss. :[

 

won't a dirty EGR system cause similiar problems?

Just throwing that out there.

 

the EGR valve can cause a miss. you can pull it, cleant it and test to see if it holds vaccum. also, i know this will sound elementary, but did you replace you fuel filter? when are you experiencing the miss?

 

Fuel system problem...clogged/dirty fuel filter. Clogged/dirty fuel injectors. If you've already eliminated vacuum leaks, plugs and plug wires.

 

cleaned the injectors, haven't changed the fuel filter. but i run clean at idle but it misses at 2800rpm to about 4200rpm then it cleans back up.

 

Could be a lot of things.
TPS
Timing
Fuel filter
Re-Check your vacuum lines
hell even your 5 and 6 ports could be fubared.

 

it ended up being a bad egr valve. or at lest when i changed it, it started to run fine idles clean and pulls pretty hard for a s4 n/a with 160xxx miles